electric mini moto gearing ratios (advice needed)

jimmyhackers

10 kW
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May 11, 2015
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600
hello i currently have two electric mini motos.

both have 300w motors(original) and 500w controllers(added by me)

one has a 10 tooth to 68 tooth and gets about 12mph. 0.147 ratio
the other has an 11 tooth to 68 tooth and gets about 15mph. 0.162 ratio

id prefer less torque and more top speed. So i need to increase my pinion gear or reduce my final drive gear

a 12 tooth to 68 tooth would get a 0.176 and a 13 tooth to 68 tooth gets a 0.191 ratio
has anyone done a more drastic ratio and what speeds have they got?

thanks in advance
jim
 
Okay, before you mess with that. . . .

You're saying there's a 500w controller now? Did you perhaps increase the voltage from maybe 24v to 36v? If so the rpm of the motor is going up at the price of some torque, so they'd be faster regardless. IF the motor really as the umph to do you any good, which my own experiments at that leaving me doubting. If all you did was put bigger wattage at the same voltage with the old motor, I'm not sure what good you've done yourself. People will offer theories, but tinkering with things I've never noticed that to be worth the bother, unless you're blowing controllers and are looking for a way around it.
 
thanks for the reply

yes, both have a 24v 500w controler now. i had 3 spares ones lying around.

originally both were paired with smaller wattage(less amps) 24v controllers, annoyingly they didnt state much useful information on them regarding power etc..but they were definately worse torque-wise than the new ones.

the new contollers had added the available amps and therefore torque so the 300w motors can run at full power now. I dont really want to add more volts as this seems to kill brushed motors in my experience:(

ive ordered some sprockets and they came today so i can mess about with gear ratios now. i currently have a 10tooth, an 11 tooth, a 12 tooth, two 68tooth and one 55 tooth to play around with.

12 to 68 = 0.176 and 10 to 55 = 0.1818 (these maybe be ok with the current motors/controller)

11 to 55 = 0.2 and 12 to 55 = 0.21818 (ill probably need a more torquey 24v 800w motor+controller to run these ratios)

ill let you guys know what speeds i get and answer my own question on here :)
 
things didnt turn out to plan. i had to do one 12 to 68 and the other 13 to 68. both ratios were terrible.

i felt much strain on the motor and the batteries. with a reduced acheivable top speed and a reduced battery life :(

i would of been better off swapping the rear larger gear tot a 64 or a 62 tooth
 
I'm surprised you didn't get anyone who maybe new a little more to answer.

So you say the controllers of the same voltage but higher wattage made your motors faster. My first thought is that they're more than the 300w they're billed as. I doubt the 800w watt will mean anything if it's 24v. As for the voltage being harder on your brushed motors, it's my understanding that's only because of the higher RPM, which you say you're getting with your higher wattage controllers so it should be the same effect. I haven't seen anything about the higher voltage causing that, I'd guess higher amperage would be harder on them because it's harder on EVERYTHING. Yeah, there should be more strain alright, to be expected.

From there you offer the vague desire to go a little faster. Not sure where you're at now. Is the motor even powerful enough to handle a closer ratio? How big are your wheels? I still just think of 36v turning the motor half again as fast as the original. I might guess that you've gone from 10mph up to meet the 12mph you mentioned with the controller providing the additional amperage the motor could handle and speed up with. The 36v might take you to 15, but that's theoretical at this point. With such low power, anything to bring a 10-15% improvement that succeeds is still so small as to be almost unnoticed, if you know what I mean.
 
i gave up on gear ratios and bought a brushed 500w motor instead. isnt much faster but has the torque now.
 
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